Use of a Three-Dimensional Detailed Modeling Approach for Predicting Root Water Uptake

Javaux et al.

2017-10-27

Why Investigate Root Architecture and Water Uptake?

Theory & History

Root-Soil Water Movement and Solute Model (R-SWMS)

Richard’s Equation


Solving Richard’s Equation

Solving Richard’s Equation Cont.

The Assumptions

  1. Soil water is preferably taken up at spatial locations where the energy to bring water to the root collar is minimized.
  2. Osmotic potential is negligible and root water capacity can be neglected.
    1. Valid under “normal” conditions. What about water stress?
  3. Soil and root parameters are constant and uniform.
  4. Soil homogeneity.
  5. No Root growth.
  6. Root water uptake is passive.

The Questions


  1. How do collar boundary conditions affect uptake?

  2. How does soil texture affect uptake?

  3. Which model parameters have what affect?

  4. Effective sinusoidal day-night cycle?

  5. Can we develop better 1D models?

Methodology: Scenarios

Table_1

Methodology: Parameters

Table_2

Effects of Soil Type

Fig_1

Reference Parameterization with Collar Boundary Condition 1

Fig_2

Effect of the Parameterization on the Root Collar Flux

Fig_3

Effect of Parameterization on the Three-Dimensional Distribution of Water Content (CBC 1)

Fig_4

Effect of Parameterization on the Three-Dimensional Distribution of Water Content (CBC 2)

Fig_5

Effect of Parameterization on the Sink-Term Profiles

Fig_6

Effect of Parameterization on the Vertical Distribution of Water Content and Flow Velocity Field

Fig_7

Effect of Parameterization on the Vertical Distribution of Water Content and Flow Velocity Field Cont.

Fig_8

Effect of Soil Type

Fig_9

Effect of Soil Type Cont.

Fig_10

Effect of Soil Type Cont. 2

Fig_11

Day-Night Scenario

Fig_12

Effective Sink Term as a Function of Bulk Water Potential and Averaged Water Content

Fig_13

Effective Sink Term as a Function of Bulk Water Potential and Averaged Water Content Cont.

Fig_14

Conclusions

What’s Missing

How Do We Fill In The Gaps?

References

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